Dreaming, how about our RV industry would focus on energy source versus energy storage. Energy storage such as state of the art Li battery is still finicky for even large company like Roadtrek, and it is expensive. Energy sources are either limited to obnoxiously loud generators, vehicle engine powered generators, shore power, or limited solar.
I wish someone would make an LPG/Gasoline/Diesel internal combustion engine, 3kW, 100-150cc, perhaps more than one cylinder, water cooled, well balanced, almost as quiet as Danfoss pump. The established and certainly not state of the art venerable, small Onan generators are ancient, gladly they don’t have flat heads
. If I recall correctly, crankshaft lubrication is by scooping oil from the oil pan with nineteen Century technology of the connecting rod scoop. It is difficult to make an air-cooled engine quiet and with current Al casting technology water cooled engine could be made small.
Or, using a crankshaft free, free piston engine with linear electric generator could make a package quieter and smaller. So, just perhaps, some good news could be coming from a recent development of free piston technology, no crankshaft, practically old technology but tuned for an electric energy generation instead of a direct propulsion. Having no side loads on the piston, due to lack of the crankshaft, could make this engine long lasting with limited need for lubrication.
Enjoy and dream.